if a person rolls doubles when tossing two dice, the roller profits $95. If the game is fair, how much should the person pay to play the game?
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The probability of wnning (rolling doubles) is 6 out of 36 or .
The probability of losing is 1- = .
Let $N be the price to pay to make the game fair:
Possible Probability
Outomes of outcome Expectation
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x p xp
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$95 1/6 95/6
-$N 5/6 -5N/6
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∑xp =
To make the game fair we set that = 0
∑xp = = 0
= 0
Multiply through by 6
95 - 5N = 0
-5N = -95
N = 19
So he should pay $19 to play to make the game fair.
Edwin